Mechanically based rear loading panel lamp



Sept- 24, M968 W. E. CARPENTER MECHANICALLY BASED REAR LOADING PANEL LAMP :2 Sheets-Sheet l Filed Oct. 15, 1965 w my um 2. Mm WM n MA Sept 24, w68 w. E. CARPENTER MECHANICALLY BASED REAR LOADING PANEL LAMP 2 Sheets-Shee'rl 2 Filed Oct. 15, 1965 MMI/fm ATTORNYS United States Patent m 3,403,370 MECHANICALLY BASED REAR LUADING PANEL LAMP Walter E. Carpenter, Cedar Grove, NJ., assigner, by

mesne assignments, to Wagner Electric Corporation,

South Bend, Ind., a corporation of Delaware Filed Oct. 15, 1965, Ser. No. 496,310 8 Claims. (Cl. 339-17) This invention relates to an improved rear loading panel lamp for use in printed circuits and more specifically to an inexpensive panel lamp having the bulb portion mechanically fastened to the lamp base and having the bulb wire leads mechanically fastened to the lamp terminals.

The device employs a novel retaining ring for securing the bulb to the base and a unique method for connecting the bulb wire leads to the lamp terminals.

In existing base loading lamps either a wedge type bulb is required with a special socket having spring loaded clasps which holds the bulb to the base, or t-he bulb is attached to the base by means of thermoplastic setting compositions or adhesives.

The prime disadvantage in use of the Wedge type lamp `-is that after the bulb has been removed and replaced from the base a number of times, the spring loaded clasps located in the socket will move further apart from each other and the bulb will become dislodged from the base during normal handling of the lamps. Also, since the electrical connection between the bulb and the lamp terminals is made through the spring loaded clasps, the eciency of the electrical connection will depend to a great extent on the force exerted by the clasps against the bulb leads. When the clasps are worn and move further apart from each other, the electrical connection will be extremely poor or may be broken entirely. In addition the Wedge bulb type lamp is more expensive to manufacture and requires more material than the lamp of the invention.

T-he use of thermoplastic cements or adhesives to hold the bulb to the base has the disadvantage of increasing the cost of the product -due to the additional steps of adding the resin '.material and baking the unit in order to set the resinous material. Further, the resin material has a tendency to ow onto the surface of the lamp terminals, which would be in contact with the printed circuit, because the terminals are exposed and are resting on the base of the lamp. This particular problem causes a high percentage of rejects during production of the lamps.

The lamp of the invention overcomes the disadvantages of the lamps now in use by employing a novel retaining ring and a new 4method for connecting the bulb leads to the lamp terminals. The retaining ring is made from a pliable material such as rubber, synthetic rubber or the Various plastic compositions having resilient properties. The ring is designed to t over the bulb, which in the preferred form is slightly tapered towards the top, and to hold the bulb firmly in place without breaking it. This is accomplished by making the ring with an inside diameter slightly smaller than the diameter of the bulb at the point Where the ring will grip the bulb. Further, the gripping edge of the ring, which holds the bulb is designed to exert a continuing ydownward force against the lbulb assuring that the bulb cannot be accidentally dislodged from the base. The ring is locked onto the base after being placed over the bulb by means of a specially Patented Sept. 24, 1968 designed ridge formed on the base and a ledge formed in the ring which mates with the ridge.

The method of attaching the bulb wire leads to the lamp terminals is done mechanically and results in a permanent electrical connection between the leads and terminals without the necessity of welding or relying upon spring loaded mounts. Further the lamp terminals are inserted into the base after the Wire leads are attached to the terminals. This eliminates the necessity for expensive machinery or skilled help which would be required if the leads were attached to the terminals after the terminals were inserted into the base. Also, the terminals are de signed with a barb so that when they are inserted into the base they cannot be removed. This is an important feature since it assures that the llamp terminals will not fall out of the base during normal handling or shipping of the lamps.

The present invention has the further advantage of being either lassembled [by workers in the field or if the unit is to be shipped assembled by personnel in a factory since it eliminates the use of thermosetting resins with its accompanying baking period, as well as the necessity for welding the bulb leads onto the terminals.

For a better understanding of the invention and the advantages thereof reference may be had to the accompanying ydrawings showing the preferred embodiment and of which:

FIG. 1 is a front view of the assembled lamp showing the printed circuit in dotted lines;

FIG. 2 is a side view of the assembled lamp showing a portion of the lamp in section;

FIG. 3 is a section taken along lines 3 3 of FIG. 2;

FIG. v4 is a top view of the lamp base without the bulb or retaining ring; and

FIG. 5 is a perspective view of a lamp terminal with a bulb wire lead attached thereto.

The lamp as seen in FIG. 1 and FIG. 3 consists of a hollow base 10, lamp terminals 11, a lamp bulb 14 and a retaining ring 12 which holds the bulb 14 to the base 10. The base 10, which can be molded from a plastic compound such as, but not limited to, the urea-aldehyde resins, phenolic resins and the melamine formaldehyde resins, comprises a rectanguler shaped bottom portion 16, a circular collar portion 18 located on top of the rectangular portion and a neck 20 formed on top of the collar.

The collar portion 18 of the base has a diametrical transverse channel 28 (see FIGS. 3 and 4) the importance of which will be explained in reference to the lamp terminals 11. The collar is formed with two stops 30 located on the top surface of the collar to prevent the lamp from being rotated any further than a specied distance when the lamp is inserted into the standard bayonet socket of a printed circuit.

The neck 20 of base 10 has openings 32 cut into the wall of the neck which communicate with the channel 28. These openings allow the terminals 1l to be inserted into the base after the base has been molded. Extending from the side wall of the neck 20 are two wing members 34 .having a cam surface 35. The purpose of the members 34 is to force the lamp and in turn the lamp terminals 11 up against the surface of the printed circuit when the lamp is mounted in the circuit. This will be explained further in reference to the assembly of the lamp.

The top section of neck is formed with a ridge 36 about its circumference over which the retaining ring 12 will slip and thereby grip the base. In addition arcuate slots 38 are cut into the neck so as to give the neck portion some flexibility. This is important in that it allows the retaining ring to be slipped over the neck portion without to much resistance and at the same time supply a retention pressure against the ring 12 when the ring is on the base.

The interior of the base is made up of a large chamber 22 which starts in the bottom portion 16 of the base and continues through the top of the base. This chamber carries ybulb 14 when the lamp is assembled. The diameter of chamber 22 should be made slightly larger at the top of the base if the bulb 14 is tapered in order to give additional support (see FIGS. 2 and 3). The interior of base 10 also has a smaller chamber 24 located at the bottom center of the larger chamber 22 and receives the lowermost portion of the bulb 14 as seen in FIG. 3. In addition there are two openings 26 located on opposite sides of chamber 24 which receive the terminals 11.

The retaining ring 12, which is molded from a pliable material, is constructed so that the opening at the top of the ring has a diameter slightly smaller than the diameter of the bulb at a point where the ring will grasp the bulb (see FIGS. 2 and 3). The edge 40 of said opening of the ring is tapered so as to form an acute angle with the main body of the ring causing the edge to rise slightly when the ring is slipped over the bulb 14. In this manner the edge will cause a downward force to be asserted against the bulb to insure that the bulb will remain in place during normal handling of the lamp.

The lower portion of the ring 12 has a ledge 42 which ts over the ridge 36 of the base. In this manner the retaining ring is locked onto the base and will not come loose during normal use of the lamp.

The bulb 14 used with the lamp of the invention is of standard type having a glass wall 44, a filament 46 and wire leads 4S. The walls of the bulb can be tapered, as shown in the drawings, or cylindrical.

The lamp terminals 11 are made of a metal having good electrical conductivity and are formed in an L shape as shown in FIG. 3. The vertical portion of each terminal has an inverted V shaped cut in it to form a barb 49 (see FIG. 5) which will engage the wall of the associated opening 26 when the terminal is inserted into the base.

As shown in FIG. 5 in the vertical portion of each terminal 11 there are two vertical cuts 50 and 52 providing a portion 54 there between which can be pushed out from the wall for reception of a wire lead 4S. After the wire lead is inserted between the portion 54 and the terminal wall, the raised portion 54 is pressed against the wire lead to insure a tight and permanent electrical connection -between the wire lead and terminal.

In assembling the lamp, the wire leads 48 of the bulb are first attached to the lamp terminals 11 in the manner described above. The bulb is then inserted into the large chamber 22, being sure that the bottom of the bulb rests in the smaller chamber 24 of the base. The terminals are then placed in the openings 26 being sure that the barbs 49 engage the walls of each opening 26.

The horizontal portions of the L shaped terminals are placed in channels 28 and are slightly raised by bending them so they will extend above the top most edge of the collar 18 and are not in contact with the bottom surface of the channel. In this manner excellent electrical contact with the printed circuit is obtanied. Further in the event the terminals are to high they will not damage the circuit since the terminals can always move downward into the channels 2S.

After the terminals and bulb are set in the base the retaining ring is slipped over the bulb and brought down upon the base until the ledge 42 of the ring engages the ridge 36 of the base. The lamp is now assembled and can be inserted into the bayonet shaped socket of the printed circuit.

When the lamp is placed in the circuit board the members 34 are placed through the bayonet socket. The cam surface 35 of member 34 will be in contact with the lower surface of the board and when the lamp is then rotated in the board the lamp will slide along the cam surface 3S of member 34 (see FIG. l). This will cause the lamp to raise thereby causing firm contact of the terminals with the circuit. As explained before if the terminals were set too high they can recede into channel 28 thereby preventing any damage to the circuit resulting from the terminals gouging into the copper surface of the circuit. The lamp can only be rotated until the stops 30 contact the edges of the bayonet socket.

It will be further understood that it is intended to cover all changes and modifications of the preferred embodiment of the invention herein chosen for the purpose of illustration which do not constitute departures from the spirit and scope of the invention.

I claim:

1. A rear loading panel lamp for printed circuits comprising:

(i) a glass bulb having lead wires extending therefrom,

(ii) at least two terminals connected to said lead wires,

(iii) a molded base having a tirst opening therein to receive said bulb and additional openings to receive said terminals,

(iv) a pliable retaining ring to slide over the bulb and engage the base, said ring and said base formed with interlocking means for mechanically locking the bulb, the ring, and the base together.

2. A rear loading panel lamp for printed circuits as in claim 1 wherein the inside edge of said ring is tapered to form an acute angle with respect to the main body of said ring so that the ring will exert a downward force against said bulb.

3. The rear loading panel lamp for printed circuits as in claim 1 wherein each of said terminals has two vertical cuts in its wall to provide a raised portion therebetween, said bulb wire leads being inserted between said portions and said terminal walls and the raised portions pressed against the wire leads to provide tight and permanent electrical connections between the terminals and said leads.

4. The rear loading panel lamp for printed circuits as in claim 1 wherein the top portion of the base has arcuate slots cut therein to provide a retention pressure against said ring.

5. The rear loading panel lamp for printed circuits as in claim 1 wherein the base is provided with wing members having a cam surface whereby the lamp is forced against the surface of the printed circuit when the lamp is rotated during mounting in said circuit.

6. The rear loading panel lamp for printed circuits as in claim 1 wherein the base is provided with stop means so that the lamp can only be rotated a specified distance when said lamp is inserted into a bayonet socket of said printed circuit.

7. An L-shaped lamp terminal for mechanically connecting bulb wire leads in a rear loading lamp comprising:

(i) at least two vertical slots in the wall of one leg of the terminal to form a raised portion therebetween for reception of a bulb wire lead between the said raised portion and said terminal wall, and

(ii) an inverted V-shaped cut in said terminal wall disposed between said raised portion and the free end of said one leg to form a barb which engages the walls of a lamp base when said terminal is mounted in the lamp.

8. A lamp terminal for mechanically connecting bulb wire leads in a rear loading lamp as in claim 7 wherein the raised portion is pressed against the wire to provide a References Cited UNITED STATES PATENTS Doty 339-217 Wood 339-217 Lagin 339-97 Woofter et al. 339-17 6 1/1962 Loesch 339-91 8/1962 Benson 339-17 3/1964 Long 339-276 4/ 1967 Sherlock 174-752 FOREIGN PATENTS 4/ 1965 Great Britain.

MARVIN A. CHAMPION, Primary Examiner. Greasley 24U-8.16 10 J. H. MCGLYNN, Assistant Examiner. 

1. A REAR LOADING PANEL LAMP FOR PRINTED CIRCUITS COMPRISING: (I) A GLASS BULB HAVING LEAD WIRES EXTENDING THEREFROM, (II) AT LEAST TWO TERMINALS CONNECTED TO SAID LEAD WIRES, (III) A MOLDED BASE HAVING A FIRST OPENING THEREIN TO RECEIVE SAID BULB AND ADDITIONAL OPENINGS TO RECEIVE SAID TERMINALS, 